OpenCart can already do this. The customer can choose their options, add the product to their cart, re-choose their options, and then add another product to the cart. The product will show up as two items in the cart.

I didn't mean that.
I know this process, what i told was:
i.e. contact lenses, same product, different options for left or right eye.
So, is it possible to have twice the options in the same product, in order the customer to add to cart once the product (which in fact will be two products, )

Ah, I see. Unfortunately there's no way to do that in a default installation, so you'll need to find an extension or have someone create a custom modification for you. If you need to find a developer, you should post a request in the OpenCart "Commercial Support" forum, which is checked by a number of OpenCart developers. You can also try checking out the OpenCart "Partners" area.